Uniform and crack free TiO 2 thin films with highly dispersed platinum were prepared from i PrOH TTIP DEA H 2O system containing H 2PtCl 6·6H 2O as metal source by sol gel method. The microstructure and morpholog...Uniform and crack free TiO 2 thin films with highly dispersed platinum were prepared from i PrOH TTIP DEA H 2O system containing H 2PtCl 6·6H 2O as metal source by sol gel method. The microstructure and morphology of the films were characterized by TEM and XRD respectively. It was found that the Pt particles dispersed in the films and had a homogeneous distribution in the shape of sphere with an average size of about 5 nm. This study also showed that the doping with few percent of Pt resulted in the formation of pure rutile phase at a temperature as low as 550 ℃, whereas the same pure phase was formed at the temperature higher than 650 ℃ in TiO 2 or Au/TiO 2 thin films.展开更多
Platinum films were sputter-deposited on two groups of nickel alloy substrates, in which the first group was the samples with rough surface, and the other group with polished surface. The platinum thin-films were appl...Platinum films were sputter-deposited on two groups of nickel alloy substrates, in which the first group was the samples with rough surface, and the other group with polished surface. The platinum thin-films were applied to serve as the low-emissivity layers to reflect thermal radiation. Then, the platinum-coated samples were heated in air at 600 ℃ for 200 h to explore the effect of high-temperature environment on the emissivity of coated platinum film. After annealing, the average IR emissivity （at the wavelength of 3-14 μm） of the platinum film was only about 0.1 for polished sample and 0.45 for rough sample. The diffusion between platinum and the nickelalloy elements at 600 ℃ had been also discussed.展开更多
To improve the accuracy of skin temperature measurements in thermal comfort research,a new measurement method based on a new thermometer is proposed.A platinum film resistance（Pt1000）sensor of the thermometer is wel...To improve the accuracy of skin temperature measurements in thermal comfort research,a new measurement method based on a new thermometer is proposed.A platinum film resistance（Pt1000）sensor of the thermometer is welded on a printed circuit board to eliminate the heat loss from the leads and avoid the influence of the surrounding thermal environment.In order to determine the suitable thickness of the board,a steady heat conduction model is established.The simulation results reveal that when the thickness of the board is 0.2 mm,the influence of the surrounding air can be effectively prevented and the skin temperature does not obviously increase.The experimental results of verification show that the maximum measurement error of the skin temperature measured by the thermometer is 0.24 ℃,and the average measurement error of the skin temperature is 0.04 ℃.The proposed method provides an effective and reliable option for the skin temperature measurement in thermal comfort research.展开更多
Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films a...Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films above 1000℃were studied in situ by TEM at the nanoscale.The Pt films degraded mainly through void nucleation and growth on the Pt-SiN_(x)interface.Voids preferentially formed at the grain boundary and triple junction intersections with the interface.At temperatures above 1040℃,the voids nucleated at both the grain boundaries and inside the Pt grains.A stress simulation of the suspended membrane suggests the existence of local tensile stress in the Pt film,which promotes the nucleation of voids at the Pt-Si Nxinterface.The grain-boundary-dominated mass transportation renders the voids grow preferentially at GBs and triple junctions in a Pt film.Additionally,under the influence of an applied current,the voids that nucleated inside Pt grains grew to a large size and accelerated the degradation of the Pt film.展开更多
文摘Uniform and crack free TiO 2 thin films with highly dispersed platinum were prepared from i PrOH TTIP DEA H 2O system containing H 2PtCl 6·6H 2O as metal source by sol gel method. The microstructure and morphology of the films were characterized by TEM and XRD respectively. It was found that the Pt particles dispersed in the films and had a homogeneous distribution in the shape of sphere with an average size of about 5 nm. This study also showed that the doping with few percent of Pt resulted in the formation of pure rutile phase at a temperature as low as 550 ℃, whereas the same pure phase was formed at the temperature higher than 650 ℃ in TiO 2 or Au/TiO 2 thin films.
基金supported by the fund of the State Key Laboratory of Solidification Processing in NWPU, NoKP200901
文摘Platinum films were sputter-deposited on two groups of nickel alloy substrates, in which the first group was the samples with rough surface, and the other group with polished surface. The platinum thin-films were applied to serve as the low-emissivity layers to reflect thermal radiation. Then, the platinum-coated samples were heated in air at 600 ℃ for 200 h to explore the effect of high-temperature environment on the emissivity of coated platinum film. After annealing, the average IR emissivity （at the wavelength of 3-14 μm） of the platinum film was only about 0.1 for polished sample and 0.45 for rough sample. The diffusion between platinum and the nickelalloy elements at 600 ℃ had been also discussed.
基金The National Natural Science Foundation of China(No.50878125)
文摘To improve the accuracy of skin temperature measurements in thermal comfort research,a new measurement method based on a new thermometer is proposed.A platinum film resistance（Pt1000）sensor of the thermometer is welded on a printed circuit board to eliminate the heat loss from the leads and avoid the influence of the surrounding thermal environment.In order to determine the suitable thickness of the board,a steady heat conduction model is established.The simulation results reveal that when the thickness of the board is 0.2 mm,the influence of the surrounding air can be effectively prevented and the skin temperature does not obviously increase.The experimental results of verification show that the maximum measurement error of the skin temperature measured by the thermometer is 0.24 ℃,and the average measurement error of the skin temperature is 0.04 ℃.The proposed method provides an effective and reliable option for the skin temperature measurement in thermal comfort research.
基金financially supported by the Basic Science Center Program for Multiphase Evolution in Hyper-gravity of the National Natural Science Foundation of China(51988101)NSFC Programs(Nos.52071003,91860202,11604006)+3 种基金the Beijing Municipal Education Commission Project(Nos.PXM2020014204000021 and PXM201901420400032)the Beijing Outstanding Young Scientists Projects(No.BJJWZYJH01201910005018)the Beijing Natural Science Foundation(No.Z180014)the“111 Project(No.DB18015)。
文摘Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films above 1000℃were studied in situ by TEM at the nanoscale.The Pt films degraded mainly through void nucleation and growth on the Pt-SiN_(x)interface.Voids preferentially formed at the grain boundary and triple junction intersections with the interface.At temperatures above 1040℃,the voids nucleated at both the grain boundaries and inside the Pt grains.A stress simulation of the suspended membrane suggests the existence of local tensile stress in the Pt film,which promotes the nucleation of voids at the Pt-Si Nxinterface.The grain-boundary-dominated mass transportation renders the voids grow preferentially at GBs and triple junctions in a Pt film.Additionally,under the influence of an applied current,the voids that nucleated inside Pt grains grew to a large size and accelerated the degradation of the Pt film.
